Resonance is what brought down the Tacoma Narrows bridge.  
 
Classic example!
 
John

...previous threads have suggested that this (The Q switch) is why Alembic's are able to emulate so many other basses.  
 
However, as Bob stated above: The wood adds by taking away. Tone coloration comes from the instrument having a naturally uneven frequency response. Some frequencies get absorbed more than others and what is left determines the tone available to the pickups.
 
Bear with me here... If an instruments body is resonating at a given frequency, the vibrational energy in the string causing that resonance is being reduced and thus the PUPs are hearing LESS of that frequency.  If this is correct, the contribution of wood to an instruments tone will be valleys rather than peaks.  I suppose string tone would have peaks???
 
I almost forgot about Adriaan's post... sympathetic resonance would result in peaks.  However, with sympathetic resonance you still have to obtain that energy from somewhere (Conservation of Mass-Energy).  
 
Please understand that when I state something as fact, it's usually a question.  I have to learn to use the ? key.
 
(Message edited by mike1762 on January 15, 2009)

Actually the wood does not have to take away. It is possible for the wood and the structure it is used in to create a feedback loop into the string & pickups thereby adding energy back into the string. This would be a type of sympathetic resonance if I remember my physics lessons of way too many years ago.  
 
Keith

Yes, I think you are describing sympathetic resonance.  But resonance is a form of energy, therefore, if we increased the vibrational energy of the string in 1 frequency range, we had to reduce it in another.  It now is clear that the wood will contribute valleys AND peaks.  The Q switch can zone in on a VIBRATIONAL peak/frequency (in the string) typical for an instrument and thus emulate its tone. (I meant ?)  
 
Is there any sort of mathematical relationship between resonant frequency of an instruments body and the vibrational energy/frequency in the string?  I imagine there are too many variables for that.
 
(Message edited by mike1762 on January 15, 2009)

Not only the physical instrument causes resonance: the filter causes resonance within the electronic circuit. This colours the signal that is coming out of the pickup(s).
 
The peaks in sympathetic resonance are feeding off of the entire vibration energy, but they may cause valleys in other parts of the frequency spectrum. The valleys can be just as defining for the sound as the peaks (scooped mids work even before you start boosting highs and lows).
 
The maths involved are extremely complex (and way beyond my comfort level) - try finding some info on Fourier analysis.

Adriaan - stop thinking and get playing
 
John.

The other guys in his office might complain about the noise. I know my colleagues would ;-)
 
graeme

That, plus it takes me an hour and three quarters to get from my office to my beloved Alembics. Stop tempting me!

An hour and 75 cents?  

Ah well, I never pretended to be a native speaker ...
 
Funny thing: before the euro, the Netherlands did have 25 cent kwartjes, unlike the rest of mainland Europe which all seemed to have 20 cent pieces (at least for those currencies that had decimals in real life). We also had paper money at 25 (not 20) and 250 (not 200) guilders. The artwork on paper money was full of colours and graphic artistry - the euros are incredibly dull in comparison.
 
So yes, I often stare at the small change in my wallet and wonder where those quarters went.

... but memory is such a fickle mistress: I forgot to mention that emblem of correct change, the 2.50 guilder coin, or rijksdaalder.